The Impact of Climate Change On Brook Trout Thermal Habitat in the United States

Within their native U.S. range, brook trout (Salvelinus fontinalis) are valued for the recreational opportunities they provide, for their socioeconomic benefits to local communities, and for their utility as an indicator of environmental health.  For brook trout, stream temperatures within their viable thermal range are vital to ensuring their survival, growth, and productivity.  Climate change will influence stream temperatures via changing air temperatures.  Changes to these key factors will likely modify the distribution and quantity of thermal habitat available for brook trout, resulting in changes in this species’ distribution and abundance.  We examined the effects of changing air temperature on brook trout thermal habitat availability in 17 streams spanning the latitudinal and longitudinal gradient of the brook trout’s native U.S. range using an air temperature-stream temperature conversion model, with climate projections from the World Climate Research Programme’s Coupled Model Intercomparison Project Phase 3 emissions scenario A1B. We found between 2.5°C and 4.3°C warming in all 17 streams between 2006 and 2056, 9 of which reached or exceed the brook trout’s upper thermal limit. Fisheries managers can focus efforts on protecting streams’ riparian zone and groundwater input to mitigate the impact of rising air temperatures on brook trout thermal habitat.